CA2796975A1 - Alarm - Google Patents

Alarm Download PDF

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Publication number
CA2796975A1
CA2796975A1 CA2796975A CA2796975A CA2796975A1 CA 2796975 A1 CA2796975 A1 CA 2796975A1 CA 2796975 A CA2796975 A CA 2796975A CA 2796975 A CA2796975 A CA 2796975A CA 2796975 A1 CA2796975 A1 CA 2796975A1
Authority
CA
Canada
Prior art keywords
light
emitting diode
light emitting
current
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA2796975A
Other languages
French (fr)
Other versions
CA2796975C (en
Inventor
Peter Brigham
Stuart Hart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sprue Safety Products Ltd
Original Assignee
Sprue Safety Products Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sprue Safety Products Ltd filed Critical Sprue Safety Products Ltd
Publication of CA2796975A1 publication Critical patent/CA2796975A1/en
Application granted granted Critical
Publication of CA2796975C publication Critical patent/CA2796975C/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/18—Prevention or correction of operating errors
    • G08B29/20—Calibration, including self-calibrating arrangements
    • G08B29/24—Self-calibration, e.g. compensating for environmental drift or ageing of components

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Fire Alarms (AREA)

Abstract

An optical smoke detector (10) is provided that comprises a light source (154), a light receiver (172), and a control circuit (130) for controlling operation of the detector. The control circuit (130) is configured to apply an unregulated voltage to the light source to cause it to emit light, to monitor the current through said light source (154) so as to monitor the light emitted by said light source (154); and to monitor the current generated by light received by said light receiver (172) so as to monitor the light received by said light receiver (172). The control circuit (130) generates a ratio signal representative of the ratio of the monitored currents; and compares the ratio signal with a reference value and generate a smoke detection signal in dependence thereon.

Claims (17)

CLAIMS:
1 An optical smoke detector comprising:
a light emitting diode;
a light receiver;
and a control circuit for controlling operation of the detector;
wherein said control circuit is configured to apply an unregulated voltage to the light emitting diode to cause it to emit light;
monitor the current through said light emitting diode so as to monitor the light emitted by said light emitting diode;
monitor the current generated by light received by said light receiver so as to monitor the light received by said light receiver;
generate a ratio signal representative of the ratio of the monitored currents;
and compare said ratio signal with a reference value and generate a smoke detection signal in dependence thereon.
2 A detector as claimed in claim 1 wherein the current through said light emitting diode is in the linear current range of the light emitting diode.
3 A detector as claimed in claim 2 wherein the current through said light emitting diode is in the range 200mA to 600mA.
4 A detector as claimed in claim 1 wherein the current through said light emitting diode is in the range 200mA to 600mA, and the ratio of the monitored currents is substantially constant for a given level of incident light and is therefore independent of supply voltage.
A detector as claimed in claim I wherein said light emitting diode is driven by a high-side semiconductor device and said control circuit is configured to switch said high-side semiconductor device ON for a preselected time period at preselected time intervals.
6 A detector as claimed in claim 5 wherein said preselected time period is 100 µs
7 A detector as claimed in claim 5 or 6 wherein said preselected time interval is seconds.
8 A detector as claimed in claim 1 wherein said light is infra-red light.
9 A method of operating an optical smoke detector comprising a light emitting diode and a light receiver, the method comprising:
energising said light emitting diode with an unregulated voltage to cause said light emitting diode to emit light;
monitoring the current through said light emitting diode so as to monitor the light emitted by said light emitting diode;
monitoring current through said light receiver so as to monitor the light received by said light receiver;
determining the ratio of the monitored currents to provide a ratio indicative of the ratio of said received and emitted light;
comparing said ratio with a reference value;
and generate a smoke detection signal in dependence thereon.
A method as claimed in claim 9 wherein the current through said light emitting diode is in the linear range of the light emitting diode.
11 A method as claimed in claim 10 wherein the current through said light emitting diode is in the range 200mA to 600mA.
12 A method as claimed in claim 9 wherein the current through said light emitting diode is in the range 200mA to 600mA, and the ratio of the monitored currents is substantially constant for a given level of incident light and is therefore independent of supply voltage.
13 A method as claimed in claim 9 wherein said light emitting diode is energised for a preselected time period at preselected time intervals.
14 A method as claimed in claim 13 wherein said light emitting diode is driven by a high-side semiconductor device and the method comprises switching said high-side semiconductor device ON for a preselected time period at preselected time intervals.
A method as claimed in claim 13 or 14 wherein said preselected time period is 100µs.
16 A method as claimed in claim 13 or 14 wherein said preselected time interval is seconds.
17 A method as claimed in claim 9 wherein said light is infra-red light.
CA2796975A 2010-04-21 2011-04-20 Alarm Active CA2796975C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB1006680.1 2010-04-21
GBGB1006680.1A GB201006680D0 (en) 2010-04-21 2010-04-21 Alarm
PCT/GB2011/000614 WO2011131937A1 (en) 2010-04-21 2011-04-20 Alarm

Publications (2)

Publication Number Publication Date
CA2796975A1 true CA2796975A1 (en) 2011-10-27
CA2796975C CA2796975C (en) 2017-05-16

Family

ID=42270625

Family Applications (1)

Application Number Title Priority Date Filing Date
CA2796975A Active CA2796975C (en) 2010-04-21 2011-04-20 Alarm

Country Status (13)

Country Link
US (1) US8866083B2 (en)
EP (1) EP2561495B1 (en)
JP (1) JP5837047B2 (en)
CN (1) CN103080988B (en)
AU (1) AU2011244147B2 (en)
CA (1) CA2796975C (en)
DK (1) DK2561495T3 (en)
ES (1) ES2469167T3 (en)
GB (1) GB201006680D0 (en)
HK (1) HK1183371A1 (en)
PL (1) PL2561495T3 (en)
PT (1) PT2561495E (en)
WO (1) WO2011131937A1 (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE212014000258U1 (en) * 2014-03-31 2017-01-27 Abb Schweiz Ag A sensor for detecting abnormal conditions of a container element and within the volume in the container element
TWM506609U (en) 2015-05-27 2015-08-11 Ind Tech Res Inst Medicament amount monitoring device of respiratory device
ES2894676T3 (en) 2016-08-04 2022-02-15 Carrier Corp Smoke detector
CN108074369A (en) * 2016-11-11 2018-05-25 基德科技公司 For smog of the aircraft based on optical fiber and/or overheating detection and monitoring
CN109062317B (en) * 2018-09-07 2020-08-07 无锡华润矽科微电子有限公司 Constant current driving circuit and corresponding photoelectric smoke alarm circuit
TWI734156B (en) * 2019-07-26 2021-07-21 義隆電子股份有限公司 Smoke sensing device
US11615684B2 (en) * 2020-11-24 2023-03-28 Pixart Imaging Inc. Smoke detector
US11913864B2 (en) * 2020-11-24 2024-02-27 Pixart Imaging Inc. Smoke detector with increased scattered light intensity
US20240078896A1 (en) * 2022-08-17 2024-03-07 Carrier Corporation Light emitter driver circuit for smoke detector

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2298757A (en) * 1938-12-10 1942-10-13 American District Telegraph Co Smoke detection system
US3946241A (en) * 1973-11-26 1976-03-23 Pyrotector, Incorporated Light detector with pulsed light source and synchronous data gating
JPS51136471A (en) * 1975-05-21 1976-11-25 Nittan Co Ltd Photocell smoke sensor
JPS5483491A (en) 1977-12-15 1979-07-03 Matsushita Electric Ind Co Ltd Smoke detector
JPS55116194A (en) * 1979-02-28 1980-09-06 Sanyo Electric Co Electrooptical smoke detector
CH657221A5 (en) * 1981-06-15 1986-08-15 Cerberus Ag SMOKE DETECTOR.
JPS60154142A (en) * 1984-01-24 1985-08-13 Matsushita Electric Works Ltd Photoelectric smoke sensor
JPS60144458U (en) 1984-03-05 1985-09-25 ホーチキ株式会社 fire detection device
JPS61172034A (en) 1985-01-25 1986-08-02 Matsushita Electric Works Ltd Sensitivity tester of photoelectric separation type sensor
US4870394A (en) 1988-01-29 1989-09-26 Systron-Donner Corp. Smoke detector with improved testing
JPH0358795U (en) * 1989-10-09 1991-06-07
US6155160A (en) * 1998-06-04 2000-12-05 Hochbrueckner; Kenneth Propane detector system
US6876305B2 (en) * 1999-12-08 2005-04-05 Gentex Corporation Compact particle sensor
GB2379977B (en) * 2001-09-25 2005-04-06 Kidde Plc High sensitivity particle detection
CN2535804Y (en) * 2002-04-16 2003-02-12 深圳市赋安安全系统有限公司 Intelligent ight-temp. composite detector
CN2624304Y (en) * 2003-05-10 2004-07-07 河北科技大学 Large space fire detector
US7847700B2 (en) * 2007-07-03 2010-12-07 Conforti Fred J System and method for an optical particle detector
WO2010124347A1 (en) * 2009-05-01 2010-11-04 Xtralis Technologies Ltd Improvements to particle detectors

Also Published As

Publication number Publication date
EP2561495B1 (en) 2014-03-19
GB201006680D0 (en) 2010-06-09
CN103080988B (en) 2015-09-23
ES2469167T3 (en) 2014-06-17
DK2561495T3 (en) 2014-06-23
PT2561495E (en) 2014-06-12
PL2561495T3 (en) 2014-09-30
US20130033699A1 (en) 2013-02-07
AU2011244147B2 (en) 2015-03-26
JP5837047B2 (en) 2015-12-24
CN103080988A (en) 2013-05-01
CA2796975C (en) 2017-05-16
WO2011131937A1 (en) 2011-10-27
EP2561495A1 (en) 2013-02-27
JP2013529296A (en) 2013-07-18
AU2011244147A1 (en) 2012-11-15
HK1183371A1 (en) 2013-12-20
US8866083B2 (en) 2014-10-21

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Effective date: 20160401